Foundries use automated matchplate molding machines to produce large quantities of green sand molds which in turn create metal castings. As is well known, sand molds typically comprise two halves, including a cope situated vertically on top of a drag. The cope and drag are separated by a horizontal parting line and define an internal cavity for the receipt of molten metal material. Sand cores may be placed in the internal cavity between the cope and the drag to modify the shape of metal castings produced by the sand molds. The cope mold has a pouring sprue to facilitate pouring of molten metal into the internal cavity of the mold. Once molten metal is received in a sand mold, it is allowed to cool and solidify. Then, the sand mold can be broken apart to release the formed metal castings.
Although manual operations exist for creating sand molds, the modern way to form sand molds is through automated matchplate molding machines. Modern automated matchplate molding machines for creating sand molds are disclosed in the following patents to William A. Hunter, U.S. Pat. Nos. 5,022,512, 4,840,218 and 4,890,664, each entitled “Automatic Matchplate Molding System”, which are hereby incorporated by reference in their entireties. These patents generally disclose automated machinery that utilizes a flask assembly comprised of a drag flask, a cope flask, and a matchplate (also known as a “pattern plate”) therebetween. The flask assembly is successively and automatically assembled, filled with sand and unassembled to form sand molds.
With advances in automated mold handling machinery, sand molds can be made very rapidly. In turn, production rates at foundries have increased several times. As a result of this increased productivity, often times it will be desirable to switch pattern plates several times during a work day as different casting orders are filled. By frequently switching pattern plates, several different jobs and castings can be completed by a molding machine to fill several different orders. However, there is a substantial amount of downtime involved with switching different pattern plates for different jobs. Pattern plates are typically bolted into the mold flask assembly, usually onto the drag flask. Manual labor is required to manually fasten and unfasten the bolts. If an automated molding machine is servicing many different jobs, this can result in several minutes or even hours of downtime during a work day.
Another type of automated matchplate molding machine is disclosed in U.S. Pat. No. 6,622,772, the entire disclosure of which is hereby incorporated by reference. This molding machine includes a turn table that rotates two mold flasks between a mold unload/service station and a flask filling station. In this machine the cope flask and the drag flask are bolted together by a bolt, which secures the pattern plate therebetween. A bolster plate, which is mounted to the turntable, supports the pattern plate during mold release operations. Automatic screwdrivers are actuated into and out of position to fasten and unfasten the bolt. While this has eliminated manual fastening and unfastening operations, the automatic screw driver concept relates to a different type of molding machine and has proved to have some reliability concerns.